VFX artist assembling layers in Nuke or After Effects—rotoscoping, keying, color correction. Final assembly point for all visual effects shots.
You're sitting in front of Nuke or After Effects with the camera plate from set, three layers of elements from the green screen shoot, plus particle simulations, roto-masks, and color correction nodes. This is your playground as a compositor—and this is precisely where it's decided whether the VFX pipeline looks coherent or chaotic in the end. The compositor isn't the effects artist who built the simulation. The compositor is the one who brings all these fragmented pieces back together into a single, believable image.
The classic work begins with plate management: you check for scratches, flicker, and exposure fluctuations. Often, you'll need to work with grade nodes here already to synchronize the color and tonality between foreground and background. Then come the elements—a CG character, particle debris, a light simulation. Each of these was rendered in isolation, with an alpha channel, perhaps also crypto mattes for easier masking. You stack these layers, use keying techniques (often with Primatte or Keylight if green fringes are still present), apply rotoscoping where automatic masking fails, and match the motion blur between CG and live-action. This is craftsmanship, labor-intensive, and requires a feel for light and geometry.
The second layer is the color matching across all layers. Not grading them individually—but in such a way that the CG character is under the same sun as the actor, that the shadows match, that reflections in the eye look believable. For this, you need 3D knowledge (where does the light in the room come from?), but also an intuitive ability to read images. Many compositors work closely with the color grader—but in the VFX pipeline, the compositor is often the first to see the final image. They decide on the transitions between synthetic and photographic.
On set day, you might also be sitting in the DIT trailer, looking at the raw data—to see where problems might arise later. In the final cut, you do several passes: rough composite (quick, for timing checks), refined composite (with all details), final (with all corrections from supervision). Often, a compositor works on 20, 30, 50 shots in parallel—each shot is a new puzzle. Effectiveness is measured by how invisible your work is.